Apparatus for forming plastic materials



1,625,514 A. O. AUSTIN ET AL APPARATUS FOR FORMING PLASTIC MATERIALS April 19, 1927.

Filed Feb. 12, 1925. '7 Sheets-Sheef 1 Fly] I l: u

G CD CD ATTORNEYS April 19, 1927.

A. O. AUSTIN ET AL APPARATUS FOR FORMING PLASTIC MATERIALS- 1925 -7 ShetS-Shet 2 Filed Feb. 12

' lliiiirk r 9 INVENTORS g BY %'MZ4 M A TTOIRNEYS A' nl 19, AUSTIN ET AL APPARATUS FOR FORMING PLASTIC MATERIALS Filed Fel'S. 12, 1925 '1 Sl'xge'ts-Sheet a INVENTORS M 0. M BY $51M! M 61M! WW ATTORNEYS April 1927' A. o. AUSTIN E AL APPARATUS' FOR FORMING PLASTIC MATERIALS Filed Fgb. 1 1925 7 Sheets-Sheet 4 W I A TTORNEYS' A ril 19, 1927, 1,625,514

A. o. AUSTIN ET AL APPARATUS FOR FORMING PLASTIC MATERIALS Filed Feb. 1 1925 M y INVEIf/TORS BY fiwJJ/LZZ/Mid Mr M Arromzvs April 19, 1927.

A. O. AUSTIN ET AL APPARATUS FOR FORMING PLASTIC MATERIALS Filed Feb. 12. 1925 '7 Sheets-Sheet 6 i!Illlllllllllllllllllllllllllllllllllllili INVENTORS W 0 M fi'u-au ATTORNEXS 1,625,514 A. o. AUSTIN ET AL APPARATUS FOR FORMING PLASTIC MATERIALS April 19 1927.

Filed Feb. 1925. 7 Sheets-Sheet '7 'illllllll H I I H INVENTORY J MA fl W a A BYflMJJMMA MIL ATTORNEYS Patented Apr. 19, 1927.

umrso s rares PATENT" Aia'rn'pnol AUSTIN Ann DONALD KEITH MAoLE'on; oFBAnBER'ToN', onIo', ASSIIGNORSI, BY MESNE ASSIGNMENTS, To THE 01:10 BRASS coiurA'iv'Y, on MANSFIELD, care; A

CORPORATION OF NEW JERSEY.

Application filed February 12, 1925: Serial No. s';s21.

This invention relatesto improvements in equipment for forming plastic material andmore particularly the forming ot ceramic bod materials althou h the im rovement is' applicable to the forming of many plastic materials. The embodiment of the invention, described herein, is designed especially for the formingofinsulators by What is commonly known as the wet process or method. While the" method may be used in forming any ceramic articles, it isparticular-ly applicable to the forming of insulators or other parts: where his desired to form a threaded hole in the piece.

The object of the invention is to provide equipment of the class named which shall be of improved construction and efiicie'nt and accurate in operation and which shall be provided with means for delinitelylimiting the thread forming operation so that uniformity and accuracy intheproduc-t will be secured.-

Theinvention is exemplified in the combination' and arrangement of parts shown in the accompanied drawings and described in the followingspecification and it is more particularly pointed out in the appended claims.

In the drawings- Fig. 1-is an elevation of a machine embodying one form of the invention with partsshown in section.

Fig. 2 is a vertical section substantially on line 22 of'Fig l.

Fig. 3 is a transverse sectionsubstantially on line 3-3 of Fig. 1.

Fig. iis a vertical sectional View showing a modified form of reversing mechanism.

*ig. 5 is a horizontal sectional view of the mechanism shown in Fig. 4.

Figs. 6, 7, 8, 9, and 10 are diagrammatic views showing the operation of the mechanism shown in Figs. 4 & 5.

' Fig-ll is a'diagrammatic view ofamoditied form of reverse.

Fig.12 is a' diagrammatic elevation of another form of reverse.- v

Fig. 13 is a diagrammatic plan of apart of Fig. 12. I

In the forming of threaded insulator parts it is customary to use parts'having threaded recesses commonly known as pin' holes. which have approximately four threads per inch. The depth ofthe pinholes usually runs from one and one-half inches to three inches; These dimensions apply particularly to the fired or finished articles, tlne allowance being made in the forming process for shrinkage ofthematerial during drying and during the-firingor'burningprocess: It is evidentg, where four threads: per

inch are used, that fora depth of pinho'le which the forming member isflttach'edr One bearing of the spindle is anut and the spindle has athread of the'samepitchasthe thread formed in the green piece. It is seen, where the spindleisrotated,that asit is driven down intotheclay orplastic mate rial, it will tend to form a thread; If-the rotation is'stopped at the end of the stroke and the spindle reversed, the plunger- 01' forming tool will be drawn out,- leaving a threadedrecess'or pinhole inthe piece.

It has been customary to use a shift mechanism to control the upward and downward positionsof the spindle or forming plunger.- This controlhasbeen effected by link-mechanism, operating on a clutch or by electrical contact reversingthe motor.

These two methods while satisfactory under many conditions, are unsuitable where accuracy is required It is evident that where a plunger or forming tool is rotated down into the clay or plastic material, the amount of travel being controlled by a clutch, that there is likely to be a considerable variation if there is any change inthe resistance of the plastic material. Where the material is soft or'the mould is'not filled with the same amount of material, there is a tendency for the inertia of the plunger and rotating PZLltSCOIillECtQCl with same totravel further before the reversing clutch or motor stops rotationandfurther downward travel.

as the stiffness of the clay, the amount of lubrication or anything that effects the friction between the forming member and. the material to be formed. Under these conditions it will be seen that the uniformity of the piece may vary as it is exceedingly diilicult to control all of the various factors.

The present invention corrects these difficulties and provides a mechanism which has many other advantages. One form of this invention is shown in Figure 1. In this figure, is a main body casting or frame to which the various parts ol the mechanism are bolted or clamped so that they may be held in proper relation. The mould 11, its into a pot or a receptacle 12, which is prevented from rotation by an arm 13, which slides up and down on a tongue 1 t. The forming plunger 15, with a threaded part 16, is attached to a rotating spindle 17. The upper end of tie rotating spindle has a threaded portion 18, operating in a fixed nut 19, which forms one hearing. The lower bearing 20, provided tor the other end of the spindle. Spindle 1'? has a pinion 21 for rotating same. The spindle is free to rotate in hearing E20, and in the nut and can also, move in a longitudinal direction, with in the necessary limits. The driving motor 22 acting through the belt 23 and pinion il-l operates a geared system which alternately rotates the spindle 1i" and the attached iiornu ing plunger 15, a definite number ot turns in the forward and reverse direction a1ter- (lately. It is the means en'iploycd to obtain this definite number of revolutions or more particularly a definite travel. and the sale guards connected with same that this invention deals with particularly.

In forming the piece, a piece of clay is placed in the mould 11 and the mould then placed in the pot 12,-\\'hcn the pot is in the position shown in i 1. The pot 12 is mounted on a piston rod 25 which has a proper head working in a chamber or cylinder 26. This chamber has two ports or openlugs 27 and 28. By admitting the air or water through the opening and allowing discharge through the opening 2?, the piston head with its attached piston rod will be forced upward until the control nut 29 pro vents further upward movement.

After pressure has been admitted to the port or opening 28. the mould lilting mechanism will be driven to its upper position which can be controlled by the nut 29 or other suitable means. The mould with the plastic material must be at the upper limit of its position before the forming plunger 15 begins hacking; out of the plastic material, otherwise the threaded portion formed by the threaded member 16 will be spoiled. By using a lifting pot or mould, the number 01 revolutions required for the lormin lj may he reduced to that necessary to unscrew the threaded portion 16 so that it will free nezaeie the plastic material. This usually requires the same number of revolutions as there are threads in the lornied piece. Where a pinhole is formed, however, which has considcrable taper, the number of revolutions required may be considerably less than the number of threads, as the thread forming part may clear the piece alter a few revolutions.

It the pressure on the lower side of the p ston head atta hed to the mould lifting mechanism is not too great, it will serve as a protection to the machine or to the parts used in forming the insulator, for it is evident that il the downward pressure exceeds that produced by the pressure on the lower side oi the piston, the mould and its lifting mecl'ianisnl will be forced downward. This is a considerable advantage where the lunger has a definite downward stroke as any mistake in the setting of the nut 29 which limits the upwm'd travel of the mould or in case the mould is not properly placed in the pot, the mould will he forced downard without causing damage to the machine.

in the 'l'orniii'ig operation the mould is lifted into its upper position atthe same time that the forming plunger 15 is rotating and traveling downward. The mould remains in the upper position until the threaded portion ll; clears the thread formed in the plastic material by the same. The pressure then applied through the port 28 is released and pressure is applied on. the upper side of the piston head through the port 22' forcing the lifting; mechanism together with the mould downward. The downward travel continues until the point is reached shown in Fig. 1. At this stage some small feet 30 to which a plate 31 is attached strike on the top of the cylinder housing. in the iieet 30 are free to move in a vertical direction, they will lilt the plate and hold the mould, allowing the pot 12 to recede as it travels further in a downward direction. This loosens the mould so that it may be lifted out of the pot either by hand or by a conveyor or loading or unloading system. W hen the mould is removed, another one may be put in its place and the operation repeated.

The invention deals particularly with the means of providinga definite travel for the spindle and the forming plunger 15 and, at the same time, produce a relative longitudinal and rotatingmotion such that threaded parts of a given pitch may be formed. The definite travel of the spindle 17 is accomplished by a gear and link mechanism which will cause the spindle to rotate backward and forward a definite number of revolutions, althouah the driving motor or mechanism rotates in one direction only. The mechanism has the advantage in that both negative and positive acceleration is controlledcwithout the-use of clutches or other mechanism.

Ini Fig. 2", the motor drives the pinion 31 which meshes with the gear 32. The gear 1 that the arm 38 and the pin 37 will have a rocking motion, the pin 37 describing anarc with the pin-39 as a center. One end of another arm 40 is attached to the common pin 37, the other end being attached by a pin 41 to the'oscillating gear 42. The crank arm of thegear 34v and the pin 41 havesuch arelationi' that the large gear will be given an oscillatory motion without producing a 2 dead center and, at the same time, permit of considerable force for'rotating the spindle during forming and reversing operations where energy is required.

In. operation, the oscillating gear 42 is driven through the link mechanism so that it. operates on a pinion 43. The pinion 43 is attached to-a beveled gear 44 which in turn meshes with a beveled pinion 45. The pinion 4'5 operates through a shaft 46 on gear 47- to rotate the spindle pinion 21 which is fixed: tothe spindlelT. It will beseen that as 'ihe oscillating'gear 42 is rotated first in one direction and then in another, the train of gears with which it is meshed will be driven in first one direction and then the other. As the spindle and pinion 21 must be rotated from- 6 to 12 times, whereas the oscillating gear 42 only makes a portion of a'revolution, it is seen that a proper gear train must be placed between the pinion and the oscillating gear 42 in order to'give the proper number of turns to thepinion 21. Unless this'is done, the oscillating gear 42 operating directly on the pinion 21' will have to be very large compared to the size of the pinion 21 By using a suitable gear train, however, the motion of the oscillating gear canbe magnified and still keep the parts rather small; The spindle pinion 21 is made-with a suiiiciently wide face so that it can be keyed solidly tothespindle, the wide face permittingit to move in a longitudinal direction without disengaging the gear 47. Owing to the link mechanism, the forming spindle and attached plunger is gradually slowed down and reversed at eachend of the stroke.

lVith the arrangement show-n, it is possible to encase the working parts and allow them to work partly or wholly in oil to in sure lubrication and reduce wear to a minimum. A machine embodying this mechanism is particularly applicable to the formingiof PitTLS where' it isnot necessary to stop the mechanism. It is possible, however, to obtain the advantage of a definite downward stroke of the forming plunger, although pieces may only be formed at long intervals. This may be accomplished by stopping the motor by any good means when the spindle is at or near its upward position or by providing a' clutch at any point in the gear train which drives gear 34 having the crank pin. All that is necessary is for this clutch to disengage at a point so that the mechanism will stop at or near the upperposition of the spindle. In practice, it is usually advisable to provide ail-operating: mechanism which will determine the relative time movements betweenthe spindleand the pot lifting the mould. Another form of mechanism for reversing the rotation of the spindle is shown in Figures 4 and 5. Fig. 4 shows a section taken through the line of the reversingspindie 17. This mechanism embodies a different principle in producing rotation, and, as a large portion ofthe circumference of the main oscillating gear'may be used inthis mechanism, a reversing motion may be obtained for wider limits without usin exceedingly large parts as in the case where the oscillating gear in 1 and 2 is used;

The pinion 21 is driven y a gear 4'? as in- Fig. 1. The gear 47 is mounted on and driven through a shaft 48, which in turn is driven by the pinion 49, meshing with a large gear 50. The large gear 50 is mounted on the same shaft or connected to a reversing gear 51. The teeth on gear 51 are located both inside and outside making a continuous path. A gear or pinion F2 meshes with teeth on the reversing gear 51. The driving pinion 52 is held in inesn by a link 59 having a pin 53 operating in a slot 54. As the driving pinion 52 is driven through a beveled gear train mounted on a shaft 55, it will cause the reversing gear 51 to rotate. The driving'gear is mounted on a housing 58 which swings about the drive shaft 57 as a center. hen the pinion 50 comes to the end of the slot 54, the driving pinion 52willnecessarily have to rotate around the pin 53 as a center. This will throw the driving pin 52 into the positionv shown in broken lines in Fig. 5. This. will reverse the direction of the gear 51 and the gear 51 will move in the other direction until'the other end of the slot 54 is reached when the driving pinion will be thrown from the inside to the outside of the gear 51. This will again reverse the direction.

This type of'mechanism has certain ad vantages as a very considerable arc of the gear 51'may be used and the changing in speed or acceleration at the end of Lhe'stroke fun may be controlled to a considerable extent by changing the length of the arm of the rocking driving pinion 52 and by changing the diameter of this pinion.

The operation is shown more clearly by reference to Figs. 6, T, S, 9 and 10. In Fig. 7 the reversing gear Si is shown with the driving pinion in mesh on the outside of the gear 5t near the point where the driving pinion starts to travel from the outside to the inside of the rack on the gear 51. .I hS the driving pinion 52 keeps on rotating, it held in mesh by the link attached to the pin 53 operating inside the slot Since the driving pinion 52 and its gear train rotates about the fixed center 5?, the gear 51 will continue to rotate in the same direction until it reaches the relative position shown in Fig. H. As the pinion continues to rotate, the direction of the rotation ol the gear 51 will be reversed until it reaches the position shown in Fig. h. when the pinion starts to travel from the inside to the outside of the rack. The mariimnn position is shown in Fig. 10. its the rotation of the pinion is continued, it will be seen by reterence to Fig. 10 that the driving; pinion will be transferred to the outside of the rack and the rotation will then be in the same direction as in Fig. .l.

The arrangen'ient is shown diagrammath cally in Fig. (3 in which a combined clutch and brake U0 is shown for starting and stopping the machine. The part (30 is thrown outward so as to engage the revolv iugr part (ll which is driven by the motor {32. This starts the rotation of the gear train. The forming spindle is driven down to its lower position and when in approximately the uppermost position the clutch ($0 is dis engaged and thrown so as to engage the braking member ca. 'lhis accomplished by a yoke attached to the part (30 which slides on a key ot the shaft upon which it is mounted. With this arrangement it is possible to allow sutiicieut time for changing the mould. even though the vertical travel of the plunger may be very small. It is evident that if the machine operates continuously. the time of the complete cycle will depend upon the rotating speed of the spindle and upon the number oi turns made by the spindle.

With the clutch arrangement, however, it is possible to use a short thread and stop the iorn'iing member in the upper position in order to permit su'l'licient time tor change. thrice the spindle oi: the machine has a definite downward movement and may be driven iorward at a rate dependent upon the pitch of the thread working in the fixed not. it is evident that a machine of this kind has aluable properties when used as a tapping machine For tap 'iing blind holes or where there ditticulty in starting a tap.

Leeann Fig. 11 shows another modification enibodymg the principles above described. In this case, the reversingrack built something; lllic a spiral stairway, as shown by lit. in this case, a pinion meshes 1n the rack 66. The pinion shaft is provided with a point 6? meshing in a, groove 68. The member (ii is keyed to a drive shatt 69. The

key operates in a slot so that the member til is free to more longgiitiulinally on the sha t. its the pinion (35 revolves the projection (57 will insure the rack meshing with the pinion. The projection (57 operating in the groove ea will move the reversing eylinder or near (39. It will be seen that the auicknos 0? reverse can be etl'ected by the radius of the groove or the rack (56 at the end of the stroke. At the upper end of the rack. the reverse will be very rapid compared l o the lower end of the rack as in the latter case there will be considerable longinai movruienl of the 'ack without ma- 'liil .ri'itation. This arrangement has the advantage in that a long reversing gear prorides lon continuous drive in one direction ,ecar train may be reduced to a alum. This arrangement also has the advantage in that it is practical to give the spindle a @0011 many more turns than in thrcase where a sector of a circle only is iii-zeal. {or the rack. Wlua'e the longitudinal movement of the spindle is considerable, it is usua ly advisable to provide the gear 21 wii h a rather small taco and maintain it in a lixed position relative to the gear train while the spindle 1? slides through a key lined in the gear 2i and sliding in a keyway Tl :lurnishes the necessary driving tort through the spindle which is in turn transmitted to the forming plunger 15.

It somewhat similar arrangement to Fig. ii is shown in Figs. 12 and 13. 111 this case the rack 72 is placed in a horizontal position. The pilot 73 causes the meshing piniou 'i lto engage the rack 72 at all times. The driving pinion 74-. is mounted in a. hourlug which is free to rotate about the axis oi the shalt T5. llith this arrangement it is possible to change the acceleration at the end of the stroke by changing the effective radius of the rack 72. It is evident that the radius of the rack is an important factor in determining the rate of rotation. \Vhile the pinion is meshing in the outer portion of he rack, the speed will be correspondingly reduced. This makes it possible to effect a quick return or, if desired, to effect a quick forming" period and a. slight return in order to grit? sullicient time for making changes tor the next cycle. In this case, the thread To mounted on the spindle is made in a separate piece so that it can be readily replaced.

o claim- 1. In combination a thread forming member, a continuously connected reciprocating drive having adefinite range of movement for advancing said member to form a thread and for arresting the advance of said member ata definite position.

2. In combination a thread forming member and mechanism for advancing and retracting said memb r, said advancingand retracting,mechanism comprising a continuously connected reciprocating drive having a definite range of movement for arresting the advance movement of said member at a definite predetermined position. v

3. In combination a thread forming member, mechanism comprising a continuously connected reciprocating drive having a definiterangeot movement for advancing said member to a predetermined position {and for arresting .themovement of said member when it reaches said position and for retracting said member, said mechanism operating to rotate said member during .the .retracting movement thereof.

4 In combination a thread forming member, mechanism comprising a continuously connected reciprocating drive having a definite range of movement vfor advancing said member to a definite predetermined .position and )for retracting said member from said position, said mechanism operating to rotate said member in one direction during its ad-.

Vance movement and in a reverse direction during its retracting movement.

5. In combination a thread forming member, mechanism comprising a continuously connected reciprocating drive having a definite range of movement for rotating said member, thread-ed means for advancing said member when said member is .rotated in one direction and for retracting said member When' said member is rotating in the opposite direction, said rotatingmechanism having .a definite limited movement to arrest the rotation of said member in one direction at a definite predetermined angular position and to reverse the direction of rotation thereof when said member has reached said position.

6. In combination a thread forming member, .a spindle for said member, a fixed nut having threaded engagement with said spindle. and mechanism comprising a continuously connected reciprocating drive having a definite range of movement for rotating said spindle, said rotating mechanism having .a definite limit of movement in one direction to provide a definite limit of movement of said threading member as it ad.- vances into the Work.

7 In combination a thread forming member, a spindle for supporting said member, a nut having threaded engagement with said .spindle and a, continuously connected reciprocatingdrive for rotating said spindle, said driveiiaving a definite range of movement to provide a fixed limit of advancement of said spindle when rotated in said nut.

8. In combination a thread forming tool and continuously connected driving mechanism for advancing and retracting said tool, said driving mechanism operating to grad ually retard the movement of said tool to bring said tool to rest at a definite predetermined position and thereafter retract said tool by a. gradually accelerated retracting movement.

9. In combination a thread forming tool, a spindle for supporting said tool, threaded means for advancing said tool When said spindle is rotating in one direction and for retracting said tool when said spindle is rotated in the opposite direction and -continu ously connected actuating mechanism for rotating said spindle, said actuating mechanism having a definite range of movement for advancing said ,tool to a definite predetermined position and operating gradually to retard said toolto bring it to arrest at said position and thereafter gradually to accelerate said tool in a reverse direction during its retracting movement.

10. In a machine for forming plastic material, the combination with a support for the material to beformed, of a plunger for forming a recess in said material, means comprising a continuously connected reversing drive for moving the plunger toward the support and for arresting the movement of the plunger at a definite predetermined position in its path of movement. I

11. In a machine for forming plastic material, the combination'with .a support for a mould, of a plunger for tormingja recess in plastic material contained in said mould, means comprising a continuously connected reversing drive for causing said plunger to approach said mould to permit the plunger to make an impression in the plastic material in said mould and for arresting the movement of said plunger When said plunger has reached a definite predetermined position relative to said mould.

12. In a machine for forming plastic material, the combination with a support for a mould, of a plunger for forming a recess in plastic material contained in said mould, means comprising. a continuously connected reversing drive for causing said plunger to approach said mould, for rotating said plunger relative to saidinould and for arresting said rotation when said plunger and mould have a definite predetermined angular position relative to each other.

13. In a forming machine for plastic material, the combination with a support for a quantity of material, a plunger arranged to approach said support, means comprising a continuously connected reversing drive for relatively rotating said plunger during said approach and tor arresting therelativerate ill tion and approach of said plunger at a definite predetcrmined position ot rotation and approach relative to said support.

ll. In. a machine tor forming; plastic material. the combination with a pair of (0111- plementanv torminc members of means comprising a. continuouslv connected reversing: drive tor causing: said forming: inemhers to approach each other :tor imparting relative rotation thereto during said approach and for arresting said relativerotation and approach when said members have attained a. definite predetermined relative position of rotation and approach.

iii. A machine 'lor tormiue; plastic materiah con'iprising a. die. threaded mechanism and a continu uslyconnected reversing: drive for said threaded meclninisni i'or sirnullanr ousl v rotating; and :ulvauciugr said die and means tor arresting raid. the at a definite pre determined position ot rcta .ion.

16. A machine tor toriningr plastic material, comprising; a support for a mould. a plunger having; a. threzuled die thereoin a continuously connected reversing drive tor advancingsaid die toward said support and for imparting; rotation thereto during said advancing movement and for arresting said die when it has attached a definite predetermined position of advancement and rotation relative to said support.

17. A machine tor forming plastic material comprising a pair of forming members relatively movable toward and away troin each other, one of said members having a threaded die thereon for forming threads in said plastic material, nicchai'iism including a contimiously connected rc'versinu; drive tor advancing said men'rhers toward each other and for simultaneously inmarting relative rotation thereto so that said members approach each other by an amount equal to the pitch of the threads on said die for one com plete relative rotation of said members and for arresting the relative movci'ncnt of said members when said members have reached a definite predetermined position of rotation and advancement relative to each other.

18. The combination with a support tor a mould ot a threaded die for one" ring plas material in said mould. nechainisni inclui' inn a continuously connect-evil reversing drive for advancing; said die into the material in said mould and tor simultaneously rotating said die to cause the tlncads thereon to term threads in the. material in said mould, .tor arresting: the movement oi? said die when it has attained a delinitc medctermincd position relative. to said mould and for reversing the rotation oti said die and retracting: the same to unscrew said die tron: said mould.

19. In a machine tor forming pl; 1c ma tcrial, the combination. vvith a support for a mould. of a threaded die for engaging: plastic material in said mould and actuating;

mechanism including a contimiouslv connected revcrsinp' drive having: a delinitc limited range or movement for advancing said die toward said mould.

20. A machine for tlorming plastic niatcrial, comprising: a. plunger having: a die thereon :lor cmraging said material and actuating; mechanism for said plunger. said actuating mechanism including a continuonsl v connected reversing drive operating); to impart movement to said plunger to a definite predetermined position and suhsequentlv to retract sa'id plunger :lrom said msition.

:l. hllochanism lor 'l'ormino' plastic nun terial. comprising: a plunger having a die thereon and actuating; nuechauisi'n for said plunger including a motor and a reversing; drive forming a continuous connection hctn'een said motor and forming; mechanism, said actuating; mechanism having a definite prcdetern'iincd range ot' rcciprocating movement.

2:2 The combination with a support lo' a mould, of a plunger having a die therooin threaded means for causing said plunger to approach said support when said plunger is; rotated and a continuously connected reversing drive for imparting a predetermined amount ct rotary moven'ient to said plunger and for reversing said movement at the limit thereof.

93. A. machine for forming plastic material comprising; a support tor a moulch a plunger comprising a spindle having a threaded die thereon, threaded means tor advancing; said spindle and die toward said mould when said spindle is rotated and actuating: mechanisn'i i0]? said spindle including a continuously connected reversing drive operating: to rotate said spindle to bring said spindle to a. definite predetermined lin'riting position both as to angular move ment and advancement relative to said support.

2i. A. machine for forming plartic material comprising a support for a mould, a plunger having; a threaded die thereon, threaded means for advancing said plunger toward said support when said plunger is rotated and mechanism for rotating; said plunger. said mechanism including a con-- tinuously connected reversing drive having; a definite range of reciprmzating movement to advance said plunger to a. definite prcdetcrmincd position and tl'iercalter revc i direction of rotation thereof to cause said plungg er to he retracted.

A machine for forming plastic ma terial comprising a support for a mould. a plunger having a threaded die thereon for engaging the material in said mould, thread ed means for advancing said plunger when said plunger is rotatech said means ha vino; threads mrresponding in pitch to the threads lll on said die and actuatingmechanism includinga continuously connectedreversing drive for rotating said plunger, sa id mechan sm having a' tde'fi-nite range of reciprocating movement to impart the necessary rotation to saidplunger to bring said die to the same predetermined position of rotation and art va-ncement relative to said support at each operation of said plunger.

'26. A machine for *torm'ing plastic material comprising a pa'irotrelativelymovable forming members for engaging the material therebetween, means for imparting a limited relatively rapid -movement of said members toward each other, means including a continuously connected rotating drive for im parting a further slower movement of said 1 embers toward each other and means for relatively rotating said members during said slower movement, said rotating means operating to arrest the relative movement of said members when said members have attained a definite predetermined relative position.

27. A machine for forming plastic material comprising a support for a mould, a plunger having a diet-hereon for engaging the material in said mould, means for moving said mould to a position adjacent said die and means for advancing said die into engagement with the material in said mould and for simultaneously rotating said die, said advancing means including a continuously connected reversing drive operating to arrest the movement of said die when it has attained a definite predetermined position relative to said mould.

28. A machine for forming plastic material comprising a support for a mould, a'

plunger having a die thereon for engaging the material in said mould, means for litting said mould to a definite predetermined position, threaded means for advancing sa'id die toward said mould when said plunger is rotated and mechanism including a continuously connected reversing drive for rotating said plunger, said mechanism having a definite range ofreciprocating movement to cause said die to advance to a. predetermined position relative to said mould and to be retracted by reverse rotation thereof when it reaches said position.

29. A machine for forming plastic material comprising a support for a mould, fluid pressure means for lifting said support to a definite position, a plunger having a threaded die thereon for engaging the material in said mould, threaded means having a pitch corresponding to the pitch on said die for advancing said plunger into engagement with the material in said mould when said plunger is rotated and mechanism for imparting rotation to said plunger, said mechanism including a continuously connected reversing drive having a definite range of spindle is threaded, the

reciprocating movement to cause said plunger to be-advzmced to a predeterm ned position relative to said mould when raised and thereafter to be retracted by reverse rotation thereof. 1

80. "In combination a thread torming tool, a spindle for supporting said tool, threaded means tor advancing said-tool when said spindle isrotated and a continuously connected reciprocating driving member having a definit-erange otmovement for alternately rotating said spindle in opposite directions.

31. In combination a. threading tool, -a spindle for supporting said tool, threaded means for advancing said tool when said spindle is rotated and mechanism for alternately rotating said spindle in opposite directions, said mechanism comprising a reciprocating member continuously connect ed with said reciprocating member and a continuously rotating member for imparting a definite range of reciprocation to said member.

32. A machine for forming plastic material comprising a plunger having a thread forming die thereon, threaded means for advancing said plunger when said plunger is rotated and mechanism for imparting rotation to said plunger, said mechanism comprising a continuously rotating member, a second rotating member and means continuously connecting said members and actuated by said continuously rotating member for imparting reciprocating rotary movement through a definite predetermined range to said second rotary member.

33. A machine for forming plastic material comprising a support for a mould, a spindle having a die thereon for engaging the material in said mould, threaded means for advancing said spindle when rotated and mechanism for rotating said spindle, said mechanism comprising a continuously rotating member, a reciprocating rotary member and link mechanism actuated by said continuously rotating member for imparting movement to said member through a definite predetermined range so that at each cycle of said reciprocating member said spindle will be advanced to a definite predetermined position and thereafter reversed to cause return movement thereof.

34. A; machine for forming plastic material comprising a support for a mould, means for raising said support to a definite predetermined position, a plunger having a thread forming die thereon for engaging the material in said mould, said plunger comprising a spindle, a nut into which said threads on said nut and spindle having the same pitch as the threads on said die and mechanism for imparting a definite predetermined amount of reciprocating rotation to said spindle to cause said support when said support is raised and thereafter to reverse the rotation of said spindle to retract said die and means for controlling said rotating mechanism to permit arrest of the movement of said die in retracted position.

35. A machine for forming plastic material comprising a support for a mould, a plunger comprising a spindle having a threaded die thereon, threaded means for advancing and retracing said spindle when rotated and mechanism for imparting rotation to said spindle said mechanism comprising a continuously rotating member, a linl-z having one end connected to said memher, a floating support for the opposite end oi said link, a reciprocating rotary member, a second link connected with said floating support and said reciprocating member to impart l'tCiPl'OCfitlOIl to said member and clutch mechanism for controlling said continuously rotating member.

in testimony Whereoi We have signed our names to this specification on this 30th day 25 oi January A. D. 192".

ARTHUR O. AUSTIN. DONALD KEITH MACLEOD. 

